1. Field of the Invention
The present invention relates to an image display apparatus, an image display method and a computer program, and more particularly to technologies suitable for displaying an image of video signals having character signals superposed thereon, such as characters and icons, in a video display area having an aspect ratio different from that of the image.
2. Related Background Art
As an image is captured in a 16:9 video mode with a video camera using a DV (Digital Video) format, video signals in upper and lower areas of an image pickup element of 4:3 aspect ratio are cut off and an image elongated in a vertical direction is output.
When this image is reproduced by a wide television having an aspect ratio of 16:9 widely used nowadays, the image is elongated in a horizontal direction and displayed correctly on the screen of 16:9.
During capturing and reproducing by a video camera, an image can be confirmed on a liquid crystal panel of the video camera. However, a liquid crystal panel is generally has a half line structure having an aspect ratio of 4:3 and has about 225 horizontal lines. The technologies proposed in Japanese Patent Application Laid-Open No. H07-294883 devises a liquid crystal drive circuit to realize wide display by thinning out video signals (horizontal lines) at a ratio of one per four scan lines when an image of 16:9 of the NTSC specifications is displayed on the liquid panel. With this liquid crystal driving method, the wide display can be realized only by modifying a liquid crystal driver circuit without dealing with signals to be input to the liquid crystal panel, so that this method is available to various systems.
This liquid crystal driving method is, however, associated with the problem that characters, icons and the like superposed on video signals are lost due to thinning-out of video signals. For example, as shown in a menu screen 40 shown in FIG. 4, a horizontal line of a character display is thinned out and it becomes very hard to recognize this character.
Similarly, when an image of the PAL specifications is displayed on a liquid crystal panel of the NTSC specifications, video signals are thinned out at a ratio of one per six scan lines. This poses the problem that a portion of a character is thinned out and it becomes hard to recognize it. To avoid this, Japanese Patent Application Laid-Open No. H09-322025 proposes the technologies of preventing a portion of a character, an icon and the like from being lost by controlling a thinning-out operation of video signals if a character and the like are superposed upon thinning-out lines.
However, the technologies proposed in Japanese Patent Application Laid-Open No. H09-322025 cannot deal with a high thinning-out ratio. When a 16:9 image of the PAL specifications among other images is to be displayed on a panel of the NTSC specifications, video signals are required to be thinned out at a ratio of 8:3 in order to display an original image thinned out at a ratio of 6:1 as the 16:9 image. A new approach to this high thinning-out ratio has been desired. Characters on the menu screen 40 shown in FIG. 4 for performing a variety of settings of the video camera, among other screens, are difficult to be recognized and users feel inconvenient.